Myocardial and haemodynamic effects of the beta-adrenoceptor blocking drug alprenolol (H56/28) in anaesthetized cats

Haemodynamic long-term effects of beta-receptor-blocking agents in hypertension: a comparison between alprenolol, atenolol, metoprolol and timolol.

1. Oxygen consumption and central haemodynamics were recorded at rest and during exercise in fifty-one men with essential hypertension (W.H.O. stage I) and repeated after 1 year on a single drug: alprenolol (n equals 10), atenolol (13) metoprolol (12) and timolol (16). 2. Mean arterial pressure was significantly reduced in all groups at rest (11-18%) and during exercise (5-11%). Heart rate was ...

Haemodynamic effects of labetalol-induced hypotension in the anaesthetized dog.

Central haemodynamic changes and regional blood flow were studied using the microsphere technique, during labetalol-induced hypotension in dogs anaesthetized with pentobarbitone and fentanyl. Labetalol 15 mg kg-1 decreased mean arterial pressure from an average of 88 mm Hg to 47 mm Hg. Mean pulmonary arterial pressure was unchanged. Cardiac output was reduced by decrease in stroke volume, while...

Pharmacological properties of beta-adrenoceptor blocking drugs

The effect of catecholamine infusions on myocardial blood flow, metabolic heat production and on general haemodynamics, before and after alprenolol (H56-28), in anaesthetized cats.

1. In cats anaesthetized with pentobarbitone sodium, infusions of adrenaline, noradrenaline (0.5 mug/kg per min) and isoprenaline (0.25 mug/kg per min) increased myocardial blood flow, myocardial heat production, left ventricular systolic and end-diastolic pressures, left ventricular +ve and -ve dp/dt max, and calculated cardiac output, effort and oxygen consumption. These effects (apart from t...

Selective beta 1 and beta 2 adrenoceptor blockade on epinephrine-induced arrhythmias in halothane anaesthetized dogs.

Beta 2 as well as beta 1 adrenoceptors have been recognized in the heart of vertebrates. They mediate a positive chronotropic action of catecholamines. We compared the effect of selective beta 1 and beta 2 adrenoceptor antagonists on the genesis of halothane-epinephrine arrhythmias in dogs. The arrhythmogenic dose (AD) of epinephrine was increased in the presence of l-metoprolol, a selective be...